Gas Tracer: Has a high sensitivity ppm sensor for detection of natural gas leaks down to 10 ppm in leak check mode. When equipped with the proper sensors, the GasTracer has both barhole and leak check modes available. The Gas Tracer has a version where the charcoal filter is removed from the CO sensor to allow for detection of H2S. The readout is displayed as ppm CO (not H2S), and there is no way to differentiate CO from H2S readings.
GX-2012: Has the capability of H2S detection with a dedicated H2S sensor. With the Gas Tracer, H2S sensor is not available.